Infection...now what?

I suspect I had a acetobacter infection two batches ago. It was a Scottish 80, tasted fine until 6weeks post bottling, now it tastes like apple cider (not vinegary though).

I have bottled my RIS since then and have an ESB waiting to be bottled.

The RIS shows no signs (as of yet) of an infection about 6 weeks post-bottling.

Is it possible for only one batch to be contaminated? Is acetobacter an infection that won't go away? Do I need to pitch all equipment? Bleach bomb? Or just PBW and a careful sanitation of my equipment?

Thanks for any and all help.

How do you know the first batch was infected? You could miss your mash temps or add too many short-chain fermentables and dry your beer out to where it tasted like apple cider.

If it were Acetobacter, it WILL taste and smell like malt vinegar, so I don't think that's what you are experiencing. Can you post your beer recipe and process?

It was Jamil Z.'s Scottish 80 recipe (extract version) from Brewing Classic Styles.

http://beerdujour.com/Recipes/Jamil/JamilsScottishExport80.htm
I used S-05 fermented in the low 60s.

It literally tasted fine from racking through 6 weeks, even after it carbed up. Then all of a sudden it turned to cider.

Did you add anything to that recipe? Honey or brown sugar or anything like that?

No, nothing added. I did primary (bucket) for 3 weeks then bottled w/ corn sugar.

It's consistent across the batch too. My 22oz bottles took longer than my 12oz to get the apple cider taste, but even the 22oz now have it.